ConfusedAboutEnergy.co.uk

If you have timber floors, mineral wool insulation* can be used between the joists to insulate your floor.  Assuming this is the only insulation measure installed in your house you can reduce the amount of heat loss through your floor by about a half and can therefore reduce your energy bill by about 7 or 8%.

To do this you need to be able to access under the floor via a trap door or you may have to lift all of the floor boards.  Professionally done this is an expensive job and may cost more than £ 1,000** .  DIY it may cost only a £ 100 for materials, but if t you have to lift your floor boards, it will be a long and difficult DIY task and will probably end up costing more than £ 100 when you find yourself repairing damage caused by lifting boards.  As a DIY task we have estimated the cost at closer to £ 300 for a smaller house.

 

	Approx % energy saving	Approx energy saving per year	Gas	Electric  (Std)	Economy 7	LPG	Fuel Oil
3 bed house	8%*	1600 kWh	£ 72	£ 232	£ 117	£ 123	£ 106
DIY payback time £ 300 install cost  (3 bed house)			4.2 years	1.3 years	2.6 years	2.4 years	2.8 years
Payback time with an installation cost of £ 800** (3 bed house, based on the below comment another quotes)			11.1 years	3.4 years	6.8 years	6.5 years	7.6 years
5 bed house	8%*	2400 kWh	£ 108	£ 348	£ 175	£ 185	£ 158
DIY payback time £ 350 (5 bed house)			3.2 years	1 years	2 years	1.9 years	2.2 years
Payback time with an installation cost of £ 1200** (5 bed house, based on the below comment another quotes)			11.1 years	3.4 years	6.8 years	6.5 years	7.6 years
**Please leave a comment if you have more prices for this to get the best figure we can.